Anticipating what could be the perfect meteor storm

(CNN) --One of the best meteor showers in decades could barrage planet Earth this weekend, raining down perhaps thousands of streaking points of light each hour during its peak.

Professional and amateur astronomers alike were preparing for the Leonid meteor shower, which takes place every November when the Earth passes through the remnants of Comet Tempel-Tuttle.

Tiny meteor fragments, often no bigger than sand grains, heat up as they speed and bounce across the upper atmosphere, producing intense flashes of light, sometimes brighter than Venus and in rare instances the moon.

The annual light show varies sporadically from sparse to heavy concentrations of celestial precipitation. This year, however, should present an extraordinary display because the Earth, which usually dodges the main Leonid debris clouds, will pass through the heart of one of them, astronomers said.

The storm could rival a memorable predecessor more than 30 years ago. One Colorado astronomer is making sure to watch.

"The last time the Lion (Leonids) roared back in 1966, I was a budding young astronomer. I was lying outside in my sleeping bag waiting in the wee hours of the morning for the meteors to start falling, but the action was slow. I dozed off," recalled Jimmy Westlake, an astronomer in Colorado.

An hour or so later, "all hell broke lose as the most intense meteor storm on record exploded over the eastern United States. Over 500,000 falling stars filled the sky in an hour's time." Unfortunately, Westlake had remained asleep.

"I've been waiting for 35 years to get another chance at this one! Where ever I have to go, I'll be in the clear with my camera," he said.

Observers in North America, Hawaii, Australia and Asian nations on the Pacific Rim should have the best views of the 2001 Leonids, which will take place overnight November 17 and 18.

The prime observation times in North America will likely take place in the hours before dawn. In New York, for example, that means 4 a.m. to 6 a.m. EST.

Nevertheless, around midnight local time could prove a rewarding time to look up. The meteor count will probably be low, but that is the time viewers will most likely see meteors that fly over the horizon right along the edge of the atmosphere. The so-called Earthgrazers often move slowly and generate long, colorful tails.

Astronomers predict meteor rates could peak as high as 8,000 an hour in some places, but caution that such forecasts are sketchy at best.

"The Leonids might surprise us," NASA astronomer Bill Cooke said. Predicted outbursts could fail to materialize and the showers could become intense when scientists least expect.

Regardless, prime time will be between midnight and sunrise on November 18. Astronomers suggest that meteor hunters watch the sky from in a darkened site as far from urban light pollution as possible.

The Leonids are so named because they seem to originate from the constellation Leo.